When Myr Battlesphere enters the battlefield, create four 1/1 colorless Myr artifact creature tokens
The Grixis color combination isn't great at ramping mana, but vampires tend to be very efficient in their cost and rely on each other for benefit, besides, you are limited to casting one collected card on each player's turn, so it's not broken right
Grey Ogre A Gray Ogre is a 3-mana 2/2
While these cards cannot transform to their other side once cast, having the freedom to decide between mana production and board presence grants a lot of freedom mid-game
It has haste, and can get +1/+1 each time a spell is cast, ideally a burn spell
That makes some sets near impossible, but I dont feel any shame over my Evolutions set missing all the IC stamped cards, or my promo set missing all the Worlds placement cards